The present invention relates to the assembly of mass termination connectors to ribbon cable, and more particularly to an improved tool for assembling mass termination connectors to ribbon cable.
Ribbon cable, consisting of a plurality of individually insulated electrically conductive wires attached to one another substantially in a plane through the use of a cohesive substance, such as plastic, has been known and used in the electronics industry for some time. The advantages in the use of ribbon cable are well-known and include a reduction of installation cost, ease of repair, and an increase in reliability. The use of ribbon cable is increasing in many industries. Ribbon cable comes in many different sizes, including 10-wire cable, 12-wire cable, 14-wire cable, 16-wire cable, 20-wire cable, and many more.
The use of ribbon cable is facilitated when mass termination connectors, such as plugs, sockets, and other types of connectors, are used. Mass termination connectors provide one electrical contact for each wire of the ribbon. Thus, a male mass termination plug for a 16-wire ribbon cable has 16 discrete male "pins," or electrical contacts, each corresponding to one of the 16 individual wires in the ribbon cable. Such a 16-pin plug would fit into a mating 16-hole female mass termination socket, itself connected to either another ribbon cable or into an electrical component or device.
The use of ribbon cable and mass termination connectors allows the connection and disconnection of multiple wires in a single operation. It also allows a quick check of multiple electrical connections through the inspection of a single connector.
The construction and configuration of mass termination connectors varies, and many different types are known. Typically, however, mass termination connectors have two parts: a body and a cover. The body includes a plurality of electrical prongs, each designed to pierce the insulation surrounding a single strand of wire in a multi-strand ribbon cable and to come into electrical contact with the conductive wire therein, without disturbing or contacting the adjacent strands of wire in the cable. The prongs are in electrical contact with the "pins" in a male connector or the "holes" in a female connector, thus providing the means through which the ribbon cable can function as an electrical conduit between a plurality of discrete points. The cover normally includes molded grooves, or depressions, to partially surround the strands of wire in the cable, thus holding the ribbon in a predetermined place. The cover also includes a latching means, or some other means, for securing and maintaining a tight fit with the body.
To secure a mass termination connector to a ribbon cable, the ribbon cable is properly aligned between the cover and the body, whereupon the cover and the body are brought together in alignment with sufficient pressure to force the prongs through the insulation and into electrical contact with the individual wires. The cover is securely fastened to the body, completing the assembly of the mass termination connector to the ribbon cable.
Because substantial pressure is required to force the prongs through the insulation, in most manufacturing processes the ribbon cable is pre-cut to the proper length and fastened to the mass termination connectors through the use of a bench press. Such bench presses usually are operated either manually or pneumatically.
One disadvantage with bench presses it that they can be used only where the mass termination connector can be assembled to the ribbon cable at a workbench. Where a connection needs to be made inside the cabinet of a device, or in some other relatively inaccessible place, it is not possible to use a bench press. Additionally, bench presses are relatively expensive tools that are cost-effective only where large quantities of assemblies are needed. As a consequence, a bench press is neither feasible nor practical where relatively few simple repairs or rewiring are taking place or where access to the work site is limited.
A few hand tools for assembling mass termination connectors to ribbon cable have been developed. Such tool are relatively expensive, and require visual monitoring of the assembly operation to ensure proper alignment of the cable between the connector body and the connector cover. Also, it is difficult with known hand tools to ensure that the proper amount of pressure is applied to the connector assembly.
Both bench presses and hand tools position the two parts of the connector on opposite sides of the ribbon cable and bring them into engagement with one another at sufficient pressure to cause the prongs of the connector body to pierce the insulation of the ribbon cable and come into electrical contact with the wires therein. With both types of tools it is important that the direction of relative movement of the two parts of the connector be in a precise, predetermined direction and that the parts be prevented from lateral movement or slippage, which could cause the piercing prongs to cut into adjacent insulation or come into contact with an adjacent wire. Also, with both types of tools it is important to apply sufficient pressure to ensure proper piercing of the insulation surrounding the several wires and proper fit of the connector body and cover, but not so much pressure as to impair the structural integrity of the connector itself, either through crushing or cracking.